1. Field of the Invention
This invention relates to a dry chemical analysis element cartridge for storing and taking out one by one a plurality of dry chemical analysis elements, in the form of a slide with a frame or a film chip without a frame, having a reagent layer which changes in its optical density by chemical reaction, biochemical reaction or immunoreaction with a specific biochemical component contained in a sample such as blood or urine.
2. Description of the Related Art
Recently, there has been put into practice a dry (dry-to-the touch) integrated multi-layered chemical analysis element with which the content of a specific biochemical component contained in a sample liquid, the activity thereof, or the content of solid component in the sample liquid can be quantitatively analyzed by only spotting a droplet of the sample liquid. Further, filter-paper-type test pieces and single or multi-layered test pieces based on improvement of the filter-paper-type test pieces have been developed and partly put into practice.
When quantitatively analyzing the chemical components or the like contained in a sample liquid using such a dry chemical analysis element, a droplet of the sample liquid is spotted on the chemical analysis element (on a spreading layer when the element is provided with the same and directly on there agent layer when the element is not provided with a spreading layer), and the chemical analysis element is held at a constant temperature for a predetermined time in an incubator (incubation) so that a coloring reaction (pigment forming reaction or discoloring reaction of the reagent) occurs, and the optical density of the color formed by the coloring reaction is optically measured. That is, measuring light containing a wavelength which is pre-selected according to the combination of the component to be analyzed and the reagent contained in the reagent layer is projected onto the chemical analysis element and the optical density of the reagent layer is measured. Then the concentration or the activity of the component to be analyzed is determined on the basis of the optical density according to a calibration curve representing the relation between the concentration of the specific biochemical component and the optical density.
The integrated multi-layered chemical analysis element generally comprises a support sheet of organic polymer and at least one reagent layer formed on the support sheet. Preferably a spreading layer is provided over the reagent layer. The integrated multi-layered chemical analysis element is generally in the form of a film chip of a predetermined shape such as a square or a rectangle. The film chip is sometimes provided with a frame of organic polymer for facilitating automated handling of the chemical analysis element. Further, there has been proposed a technique in which a plurality of the chemical analysis film chips without frame are loaded in a cartridge and the cartridge is loaded in a chemical analysis film supplier of a biochemical analysis apparatus so that the film chips are taken out from the cartridge one by one.
In the dry chemical analysis element cartridge disclosed, for instance, in Japanese Unexamined Patent Publication No. 5(1993)-188058, a plurality of dry chemical analysis elements in the form of a film chip without frame (will be referred to as xe2x80x9cframeless chemical analysis elementxe2x80x9d, hereinbelow), while the chemical analysis element with a frame will be referred to as xe2x80x9cchemical analysis slidexe2x80x9d, hereinbelow) are stacked in a cartridge casing, an element take-out port is formed in a side wall of the cartridge casing near to one end face of the casing and connected to an access opening formed in the end face, and a suction pad is brought into contact with one of the frameless chemical analysis elements in the casing through the access opening and laterally moved holding the frameless chemical analysis element under suction force to take out the element through the element take-out port. The stack of the chemical analysis elements are urged toward the access opening by an urging member disposed on the end face opposite to the end face in which the access opening is formed.
Further, there has been known a chemical analysis element cartridge in which a plurality of chemical analysis slides are stacked in a cartridge casing, an element take-out port is formed in a side wall of the cartridge casing near to one end face of the casing, a pressing member is disposed inside the casing to press the stack of the elements from the side remote from the element take-out port and to be movable only toward the element take-out port, the pressing member is moved toward the element take-out port by a plunger to bring the chemical analysis slides to the element take-out port one by one, and the element brought to the element take-out port is ejected through the element take-out port by a pusher blade.
In the chemical analysis element cartridge, a relatively large number of (e.g., 50) chemical analysis elements are stacked in the cartridge casing. When such a large number of elements are loaded in the cartridge, the service life of the chemical analysis elements expires before all the elements in the cartridge are consumed in the case the chemical analysis elements in the cartridge are for a minor measuring item or in the case of a user whose volume of business is relatively small. After the service life expires, the residual chemical analysis elements are generally discarded since after the expiration of the service life, the measuring accuracy deteriorates due to change in the properties of the chemical analysis elements due to, for instance, moisture absorption, which adds to the cost.
Though it is possible to load a relatively small number of chemical analysis elements in a cartridge casing which contains a larger number of chemical analysis elements, this approach is disadvantageous in that even if the number of chemical analysis elements loaded in the cartridge casing is small, a pressing member or an urging member for holding the chemical analysis elements in a stacked state is required, which adds to the cost more as the number of chemical analysis elements to be loaded in the cartridge casing becomes smaller.
In view of the foregoing observations and description, the primary object of the present invention is to provide a chemical analysis element cartridge in which a relatively small number of chemical analysis elements are contained and can be successfully taken out one by one without using a pressing member or urging member.
In accordance with the present invention, there is provided a dry chemical analysis element cartridge comprising
a box-like cartridge casing in which a plurality of chemical analysis elements are stacked and are taken out through an element take-out port formed at one end of the cartridge casing, wherein the improvement comprises that
the inner dimension of the cartridge casing in the direction of stack of the chemical analysis elements is smaller than the longitudinal and transverse dimensions of each of the chemical analysis elements.
A spacer for changing the effective inner dimension of the cartridge casing in the direction of stack of the chemical analysis elements may be provided inside the cartridge casing.
In the dry chemical analysis element cartridge of the present invention, since the inner dimension of the cartridge casing in the direction of stack of the chemical analysis elements is smaller than the longitudinal and transverse dimensions of each of the chemical analysis elements, each chemical analysis element cannot be turned over or erected on one side thereof inside the cartridge casing and can be held in a stacked state without a pressing member or urging member for preventing the chemical analysis element from being turned over. Accordingly, the chemical analysis element cartridge can be manufactured at low cost. Further, since a relatively small number of chemical analysis elements can be loaded in the cartridge, all the chemical analysis elements in the cartridge casing can be consumed before the service life expires even if the chemical analysis elements in the cartridge are for a minor measuring item or the volume of business of the user is relatively small, whereby the residual chemical analysis elements which must be discarded due to expiration of the service life can be lessened and deterioration in measuring accuracy due to change in the properties of the chemical analysis elements can be prevented.
Further, when a spacer for changing the effective inner dimension of the cartridge casing in the direction of stack of the chemical analysis elements is provided inside the cartridge casing, the inner dimension of the cartridge casing in the direction of stack of the chemical analysis elements can be adjusted according to the number of chemical analysis elements loaded in the cartridge casing and/or the thickness of each of the chemical analysis elements loaded in the cartridge casing so that movement of the chemical analysis elements relative to each other during transportation of the chemical analysis element cartridge is prevented and the chemical analysis elements can be prevented from scratching each other.